Hydraulic motors are mechanical actuators that convert hydraulic pressure and flow into torque, i.e., rotation. Hydraulic motors are utilized in many different applications, such as but not limited too, winches, crane drives, wheel motors for heavy duty equipment such as military vehicles, self driven cranes and excavators, drilling rigs, trench cutters, etc.
The hydraulic motors may operate in a single direction only, or in both a first direction of rotation and an opposite second direction of rotation, i.e., the hydraulic motor may operate in both a forward and reverse direction. Additionally, the hydraulic motors may operate at a first speed or a second speed. The first speed is generally a lower speed producing a higher torque output, while the second speed is generally a higher speed producing a lower torque output.
The hydraulic motors may include a control device to control the speed of the hydraulic motor, i.e., to switch operation of the hydraulic motor between the first speed and the second speed. If the hydraulic motor is configured to operate in both the first direction and the opposite second direction, then the control device must be capable of switching the operating speed of the hydraulic motor when the hydraulic motor is operating in both the first direction and the second direction.